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Are different reference intervals for methylmalonic acid and total homocysteine necessary in elderly people?
Author(s) -
Joosten Etienne,
Lesaffre Emmanuel,
Riezler Reiner
Publication year - 1996
Publication title -
european journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 84
eISSN - 1600-0609
pISSN - 0902-4441
DOI - 10.1111/j.1600-0609.1996.tb01367.x
Subject(s) - methylmalonic acid , reference range , homocysteine , medicine , confidence interval , reference values , vitamin b12 , vitamin , folic acid , physiology , endocrinology
To determine whether age‐adjusted reference intervals for methymalonic acid (MMA) and total homocysteine (tHcy) are necessary, data from 2 previous studies were used. First, the reference intervals for serum vitamin B 12 , folate, methylmalonic acid and total homocysteine were determined in 2 reference sample groups: 99 healthy adults and 64 selected healthy elderly subjects living at home. Secondly, health‐related reference limits were estimated in 143 elderly subjects after supplementing the nutritional status with a combination of vitamin B 12 , vitamin B 6 and folate during a 3‐wk period. In the latter group, the adjusted reference intervals for MMA (46–288 nmol/L) as well as for tHey (5–13.6 μmol/L) are different with considerably lower upper reference limits than that estimated with the original reference values (72–476 nmol/L for MMA; 6.8–21 μmol/L for tHcy) in the elderly subjects. Our data suggest that the MMA and tHcy levels increase with age. Moreover, the upper reference limit for MMA and tHcy, conventionally defined as the mean +2 SD in a healthy elderly reference sample group without supplementing the nutritional status, might result in falsely high values due to a high prevalence of an inadequate vitamin B 12 , vitamin B 6 and folate status.